Fairyfly - Unknown material error

grasshopper fairyfly
1

Hi [@chris ],
Translating my old Legacy Therm files to the new FF, I get this error on many of them:
Runtime error (ValueErrorException): THERM simulation failed. Open the thmz file in the THERM interface for more info.
Sun Jan 25 11:31:02 2026
C:\WorkingFolder\Courses\Rhino-Grasshopper-Diva\LadybugTools_2020\honeybee-grasshopper.0.0.06\EXAMPLES\fairyfly-grasshopper-master\samples\IS_Walls\03_IS_THERM_DoubleBlockWall_MiddleInsulated.thmz
Error: Unknown material: Calculation not successful
2

Traceback:
line 54, in run_model, “C:\Program Files\ladybug_tools\python\Lib\site-packages\fairyfly_therm\run.py”
line 79, in script
The thmz file is created and when opening in Therm, of course, it complains about the same error. The thiing is that when showing the preview model [material attribute] it looks fine. You can see here side by side FF/Therm. The therm shows one of the polygons as missing material.

Screenshot 2026-01-25 113230
Screenshot 2026-01-25 1132301520×999 107 KB

I can’t get why this is happening. The material are mine.
Attached the thmz, the FFjson [so you can get the whole definitions], and the GH, hoping you can get the whole information to understand the issue.
In THERM when i set the material as the same one at the top [blue] it runs fine, so the question is why the geometry at the bottom is not getting the material for the simulation but it does for the preview.

Thanks,
-A.
03_IS_THERM_DoubleBlockWall_MiddleInsulated.zip (1.7 KB)

03_IS_THERM_DoubleBlockWall_MiddleInsulated_THMZ.zip (4.8 KB)
FF_Material_Error.gh (55.9 KB)

2

Thanks, @AbrahamYezioro .

It seems like a bug where Fairyfly is not writing the material correctly. I’ll take a deeper look at the FFJSON but what type of material is this “IS_CB38-4-20x40x20-030-1-13-2” one that is not translating?

3

Actually, I can see that the FF Shape components in your Grasshopper file are from a week ago (version 1.9.2). So I think you might be experiencing a bug that was already fixed. Try updating fairyfly and running the LB Sync Grasshopper File component. Then, you should see that the component version becomes 1.9.4:

image

And I think that version of the script should run well in THERM.

4

Thanks @chris !
This solved this one. This wall section runs fine.

I’ll report a different error in a different thread.

-A.

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